Antibodies are polypeptides which are capable of binding specifically to compounds against which they were raised. Antibodies are used for a variety of purposes, such as immuno assays. More recently, their application in detergent and cleaning applications has been proposed. WO-A-98/56885 (Unilever) discloses a bleaching enzyme which is capable of generating a bleaching chemical and having a high binding affinity for stains present on fabrics, as well as an enzymatic bleaching composition comprising said bleaching enzyme, and a process for bleaching stains on fabrics. The binding affinity may be formed by a part of the polypeptide chain of the bleaching enzyme, or the enzyme may comprise an enzyme part which is capable of generating a bleach chemical that is coupled to a reagent having the high binding affinity for stains present on fabrics. In the latter case, the reagent may be bi-specific, comprising one specificity for stain and one for enzyme. Examples of such bi-specific reagents mentioned in the disclosure are antibodies, especially those derived from Camelidae having only a variable region of the heavy chain polypeptide (VHH), peptides, peptidomimics, and other organic molecules. The enzyme usually is an oxidase, such as glucose oxidase, galactose oxidase and alcohol oxidase, which is capable of forming hydrogen peroxide or another bleaching agent. Thus, if the multi-specific reagent is an antibody, the enzyme forms an enzyme/antibody conjugate which constitutes one ingredient of a detergent composition. During washing, said enzyme/antibody conjugate of the detergent composition is targeted to stains on the clothes by another functional site of the antibody, while the conjugated enzyme catalyses the formation of a bleaching agent in the proximity of the stain and the stain will be subjected to bleaching.
Little attention has been paid so far to the manner in which such antibodies are added to the detergent composition in order to achieve the desired bleaching effect of the enzyme-antibody complex. It was found that the storage stability of the antibodies in such cleaning compositions problem is not always satisfactory. Extensive prior art exists regarding the granulation of enzymes for use in detergents, but this technology cannot be directly transferred to antibodies.
The purpose of the present invention is to provide a method by which antibodies can be incorporated into (bleaching) detergent compositions in a stable manner.
It has now surprisingly been found that it is possible to incorporate antibodies into detergent compositions in a stable manner if the antibodies are granulated with simple salts, such as sodium or potassium salts. This is the converse to granulation of enzymes, whereby complicated measures have to be taken in the granulation technology in order to provide the required stability and the lifetime of the enzyme.
Moreover, it was surprisingly found the antibody activity was improved when they were stored in the granulated form, as compared to common protein storage methods. This therefore imparts a substantially improved lifetime of the antibody and its associated performance in a powdered form or product form.